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Correlation of ring nitrogen substituents with carbon‐13 nuclear magnetic resonance data in azoloazines
Author(s) -
Pugmire Ronald J.,
Smith James C.,
Grant David M.,
Stanovnik Branko,
Tišler Miha,
Verček Bojan
Publication year - 1987
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570240351
Subject(s) - chemistry , chemical shift , ring (chemistry) , substituent , nitrogen , carbon 13 , pyridine , linear correlation , carbon fibers , stereochemistry , computational chemistry , nuclear magnetic resonance , organic chemistry , nuclear physics , physics , statistics , mathematics , materials science , composite number , composite material
Carbon–13 nuclear magnetic resonance data have been acquired on 22 azoloazines. Chemical shifts have been correlated by a step–wise linear multiple regression with nitrogen substituents in both the 5‐ and 6‐membered rings using pyrrolo[1,2‐α]pyridine as the reference for chemical shift correlation. The data demonstrate that a highly correlated set of chemical shift parameters exist. Nitrogen substitution in the five–membered ring produces larger cross–ring effects than are oberved in the five–membered ring when substitution occurs in the six–membered ring. Within the six–membered ring a constant para ‐ substituent parameter is noted. The meta ‐ and para ‐ parameters are more complex and fall into two groups for each parameter. Within the five–membered ring, a highly regular chemical shift pattern is observed which reflects an attenuated perturbation from nitrogen substitution in the six–membered ring.